SBK2 and central nervous system cancer: Fluorophores conjugated to the integrin-targeting peptide RGD (IRDye 800CW-RGD) [43] or the protein tyrosine phosphatase mu-targeting peptide SBK2 (Cy5-SBK2) [7] showed a TNR of 16.3–79.7 and 11.7–19.8, respectively, dependent on the glioma cell line being observed.